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Airspeed Arc markings
Posted: Thu Jun 29, 2006 4:47 pm
by schefler
I have my instruments being overhauled and the shop needs the airspeed indicator markings. I don't have them. Its a 1950 170A with the 145.
Anybody have them?
Art
Posted: Thu Jun 29, 2006 6:13 pm
by briancbaker
Hey Art,
I think you'll find what you need on page 8 of the Owners Manual under Airspeed Limitations (available on the Members Page).
Hope that helps!
Posted: Thu Jun 29, 2006 6:49 pm
by cessna170bdriver
I notice that page 8 doesn't specifically state the lower ends of the white and green arcs. If I interpret page 13 correctly, the flaps-down, power-off stall speed is 53 mph (bottom of white arc), and the flaps-up power-off stall speed is 58 mph (bottom of green arc).
Put a white arc from 53 to 100 mph (flap operating range); a green arc from 58 mph to 140 mph (normal operating range), a yellow arc from 140mph to 160 mph (caution range), and a red line at 160 mph (never exceed speed).
This seems to agree with the manual and the most current certification standards:
FAR Part 23.1545. In addition,
FAR 23.1563 requires a placard stating maneuvering speed (115 mph) although I have seen airspeed indicators with a blue line at this speed. Maneuvering speed isn't mentioned in 23.1545, but I think that as long as your're marking the airspeed indicator anyway, it's a good idea to have a reminder. Anyone who is conscious and breathing on their own should be able to count the number of engines on the 170 and not confuse the blue line for a multi-engine best rate of climb speed with one engine inop. Anyone else feel free to chime in here.
Miles
Airspeed Arcs
Posted: Thu Jun 29, 2006 8:05 pm
by schefler
This organization never ceases to amaze me. I want to thank everyone for their helpfulness. I always get a fast response to any question I have.
What a great bunch!!
Art
Re: Airspeed Arcs
Posted: Thu Jun 29, 2006 9:02 pm
by cessna170bdriver
schefler wrote:This organization never ceases to amaze me. I want to thank everyone for their helpfulness. I always get a fast response to any question I have.
What a great bunch!!
Art
Keep the questons coming! I've learned a lot just by researching questions like this. '98C still has her original airspeed indicator, but if I ever want or have to replace it, I can come back here for the markings. The B-model stall speeds may be different by an MPH or two, but the idea is still the same.
Miles